Solar System Log by Andrew Wilson, published 1987 by Jane's Publishing Co. Ltd.

Identical to Venera 5, Venera 6 reached Venus after performing 63 communications sessions with Earth and one midcourse correction on 16 March 1969 at a range of 15.7 million kilometers from Earth. Its 405-kilogram lander separated from the main bus 25,000 kilometers from Venus and entered the Venusian atmosphere at a velocity of 11.17 kilometers per second at 06:05 UT on 17 May 1969.

The Venera 6 capsule transmitted data for 51 minutes before contact was lost. It indicated an altitude of about 10 to 12 kilometers at the end, but its atmospheric pressure reading was similar to that measured by Venera 5 at a much higher altitude, indicating that Venera 6 may have come down over a mountain or high plateau. Landing coordinates were -5° latitude and 23° longitude.

Results from the Venera 5 and 6 missions, published by the Soviets in March 1970, seemed to confirm and sharpen earlier findings from Venera 4. The two new spacecraft found that Venus's atmosphere was composed of roughly 93 to 97 percent carbon dioxide (the remainder was split among nitrogen, oxygen, and inert gases). Data from Venera 6 suggested that the ground pressure was about 60 atmospheres and ground temperature was about 400°C. This compared with Venera 4's readings, which indicated pressure at 75 atmospheres and temperature at 500°C.

Key Dates

10 Jan 1969: Launch

17 May 1969: Atmospheric Descent (06:05 UT - 06:56 UT)

Status: Partial Success

Fast Facts

This was the third successful Soviet mission to Venus.

It was the twin of Venera 5, which arrived at Venus a day earlier.

Carried a medallion bearing the coat of arms of the U.S.S.R. and a bas-relief of Lenin (above) to the night side of Venus.